\documentclass{standalone}
\usepackage{tikz}
\usepackage{ctex,siunitx}
\setCJKmainfont{Noto Serif CJK SC}
\usepackage{tkz-euclide}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{circuitikz}
\usetikzlibrary{patterns, calc}
\usetikzlibrary {decorations.pathmorphing, decorations.pathreplacing, decorations.shapes,}
\begin{document}
\small
\begin{circuitikz}[>=latex, scale=1]
  \useasboundingbox(0,0.2)rectangle(4,3.7);
\foreach \x in {.5,2,3.5}
{ 
   \draw[->] (\x, 3.7)--(\x, 0.2);
}
\node at (2.4, 0.2)[above]{$B$};
\draw[->] (1.5, 3)--(2.5,3) node[right]{$v_1$};
\draw[->] (1.5,3)--(1.5, 1)node[below]{$v_2$};
\draw[->] (1.5,3)--(2.5,1)node[right]{$v$};
\draw [fill=white] (1.5, 3) circle (1.5pt);
\node at  (1.6,2.5){$\theta$};
\end{circuitikz}
\end{document}